Amazon.com appears poised to launch a subscription e-book service offering unlimited access to about 600,000 titles.

The service would be called Kindle Unlimited and allow customers to download select e-books for $9.99 per month. Amazon briefly posted details of the service to its website, as noted earlier by GigaOm.

Kindle Unlimited would compete with subscription startups like Oyster and Scribd. Scribd offers access to more than 400,000 titles for $8.99, while Oyster offers access to more than 500,000 e-books for $9.95. Both services compensate publishers after a specific threshold of each title has been read.

In a statement, Trip Adler, CEO of Scribd, said that the “apparent entrance of Amazon into the subscription market is exciting for the industry as a whole….Publishers, authors and readers alike have all seen the benefit, so it’s no surprise they’d want to test the waters.”

Among the titles displayed prominently on the Amazon page introducing the proposed subscription service are the three novels that make up Suzanne Collins’ post-apocalyptic “Hunger Games” trilogy published by Scholastic.

A spokeswoman for Scholastic said that Amazon had the contractual right to put its e-book titles into a subscription program and didn’t need to strike a new agreement. She said Amazon had informed Scholastic of its intentions.

Scholastic, she added, will be compensated for each book read in the subscription program as though it was a typical Kindle sale. However, she said she was uncertain whether compensation would be tied to a threshold level of text that consumers have to read in order for a title to be counted as a “sale.”

Arthur Klebanoff, CEO of e-book publisher RosettaBooks LLC, said his distribution contract with Amazon gives Amazon a wide array of rights as long as Amazon pays the agreed-upon wholesale price of each title.

“We think subscription books are an excellent way to build the digital books business,” said Mr. Klebanoff. “The longer term question is where compensation eventually settles in.” RosettaBooks publishes about 600 titles.

The page promoting Kindle Unlimited is no longer visible. An Amazon spokeswoman didn’t respond to a request for comment.

Subscription e-books services have struggled to draw the newest releases from publishers, who are reluctant to forgo e-book and physical-copy sales that tend to be more profitable.

Amazon has been aggressively launching new services and products this year, including unlimited streaming music and devices like the Fire TV set-top box and Fire smartphone, due out later this month.

- This post has been updated with comments from Scribd and Scholastic.